I feel like a lot of people doesn't understand the message of this game, so I'll try to clarify my way of viewing the game.
The game is about bullying, it's pretty easy to see. If you look into the game as a whole, the mechanics, the foes, etc. you see the pattern of what goes inside the head of a bullied person.
1:You can't deal with thefoes directly, you can jump on their head (answer to what they says, punch back) but you will never be able to get rid of em. The only way you can is if you avoid them, and even then, you might not be able and have to endure it from time to time.
2: On many level, there was some way that ended in a dead end. That's pretty much how you see things when you're being bullied: There's no escape to it.
And finally, the ending. Many people see the ending as a suicide, I don't. Here's what I personally interpret it.
The last jump is not a jump from a cliff. If it would be, the game would end right there. Instead, you continue and can go right to get some lines of dialogue from your mother, one of em being adressed to the kid 'Everything is gonna be alright sweetie.'.
So what is it? It's simple. The kid didn't commit suicide, he attempted or succeded at murdering one of the bullies. The last jump is not a physical jump, it's a psychological jump (Since the game seems to take place inside the boy's head). That jump is from being sane to insane, not being able to take no more. So he fights back, and as in many sad case, he fights back a bit too strongly. But hey that's just a theory.
A game theo- (Get shot for copyright issues)